Supermoon in Washington

A supermoon rises behind the Washington Monument, Sunday, June 23, 2013, in Washington.

This year the supermoon is up to 13.5 percent larger and 30 percent brighter than a typical full moon is. This is a result of the Moon reaching its perigee - the closest that it gets to the Earth during the course of its orbit. During perigee on June 23, the moon was about 221,824 miles away, as compared to the 252,581 miles away that it is at its furthest distance from the Earth (apogee).